I was going to respond with "Protestantism", but then I realized that I also lived in the US for ~5 years and I had no problem to adapt there. Mind you, I wouldn't go back to live in the US unless you were paying me a lot of money to do so, but at least there I felt integrated.

But honestly I don't have a better answer. Despite all my sincerest efforts, I never got the German idea of humor. I never understood their lack of flexibility in social settings. Their relationships with their family members (especially parents) is completely alien to me. I certainly don't like their "one-size-fits-all" for all sorts of socio-economic policies and how that translates to the EU. I am still annoyed by the fact that I can not find a way to go back to swimming in some structured capacity: it's either the overcrowded public pools or the "you need to be at competition-ready level to join a Schwimmverein". I find it weird that I've been living in the same building for 7 years and I know basically nothing about my neighbors - except the ones living under me who repeatedly complained about us being loud (we were not) and only stopped after taking us to court and losing the case.